Using the accepted cardiomyopathic Syrian hamster as our model for hereditary avascular congestive heart failure, we wish to examine the early neonatal pathogenesis of myocardial disease. We shall employ techniques of morphology (quantitative electron microscopy) and function (ion flux, electrophysiology, tissue culture). Due to the lack of information on pre-myolytic myocardial tissue, we will examine neonatal tissue from both the myopathic strain (BIO 14.6) and normal hamsters (RB). We will study the ultrastructural alterations in subcellular organelles (volume to mass ratios of certain organelles) during normal and pathological development. Due to the implications of calcium in cardiomyopathies, we will examine transsarcolemmal and subcellular calcium transport. Such an inter-disciplinary approach will help establish a greater understanding of normal and pathological growth of the mammalian heart.